I am pretty sure this is a very well known issue, if you google it. I would think Apple should be sorting this out even if your machine is out of warranty. Read a fair bit about it recently in various threads like this. Along the lines of the machine not being fit for purpose, and it being such a well known issues its all over the usual forums and people reporting it. Only thing is I believe, Apple haven't recognised it as an issue yet, or product recall or whatever it is they do. I have a 2011 mbp also, so am keeping a close eye on things like this incase it happens to me.